The present invention is generally related to the field of pilings utilized for the support of above grade structures, and specifically to the creation of in-situ pilings by the disposition of binding material, or binder, within a borehole by a tool assembly. Together with a portion of the soil whose volume it replaces, and water which is either added or already present in the borehole, the binder forms an in-situ piling which is used as an alternative to conventional pilings. The finely powdered binder is typically transported to the tool assembly from a bulk storage container or pod by blowing air into the pod and the delivery lines. However, one factor which can adversely impact the integrity of an in-situ piling is pockets or void spots resulting from air entrained within the binder. It is desirable to deliver the binder to the borehole with a minimal volume of air.